Gender

Coronary artery disease is much more common in older people and in males. But slowly, women are catching up, and deaths from heart disease are evenly split between men and women. A number of studies report higher mortality rates from heart attacks in women. Although women tend to be older and sicker when they are first treated for a heart attack, a number of studies have indicated that these factors do not entirely explain the differences. Evidence has suggested that women, particularly the elderly, are less aggressively treated than men for all phases of heart disease, including angina attacks and heart attack. In one study women were given fewer beta-blockers, anti-clotting medications, and surgical procedures than men and were treated an average of 14 minutes later with time-critical thrombolytic treatments. It appears to be younger women, however, who are at greater risk of death from a heart attack than men their own age. One possible explanation for the later treatment and higher death rate in younger women is the possible failure to recognize symptoms in this population, particularly in younger women. 

Ethnicity

In a 1998 analysis, the mortality rates from coronary artery disease declined between 1987 and 1994 in both Caucasians and African Americans; however it is decreasing significantly in Caucasians but not in African Americans. African American women still face the highest risk for death from heart disease, and their rate of heart attacks are increasing. Although socioeconomic factors, such as poor diet, higher stress levels, and lack of access to health care certainly play significant roles in these differences, biologic factors may be involved in certain people. Some African Americans with coronary artery disease appear to have a genetic trait that increases the danger of triglycerides, a particular risk factor in women. One study found that African Americans produce less nitric oxide in response to stress; this substance is critical for opening blood vessels and increasing blood flow. Native Americans, particularly those in North and South Dakota, also face a much higher risk for heart disease than whites. Hispanics have a lower risk for heart disease than all these groups.

Smoking

Smoking contributes to the development of atherosclerosis by lowering HDL levels and causing deterioration of elastic properties in the blood vessels which reduces blood flow. Cigarette smoking is directly responsible for nearly 20% of all deaths from heart disease, and smokers are 2.5 times more likely to suffer heart attacks than are nonsmokers. They are also more at risk for death from a heart attack. Women who smoke have an even higher risk than male smokers. Secondhand smoke also increases the risk of heart attack in non-smokers. One study showed that those living with heavy smokers have a four-fold higher risk of heart attack. Quitting usually reduces the risk for a heart attack, although evidence suggests that at least some of the smoke-induced damage in the arteries may be irreversible. 

Cholesterol and Lipids

Total cholesterol levels should be 200 mg/dl or less. In healthy people LDL cholesterol levels should be 160 mg/dl or below and in people with coronary artery disease LDL should fall below 100 mg/dl. The lower the better. HDL levels should be well above 35 mg/dl. (An HDL level above 60 may offer enough protection to cancel out a risk factor.) Triglyceride levels should be under 200 mg/dl, although some experts recommend that they be under 100. Elevated levels of other lipids, including lipoprotein (a) and apolipoprotein A-1 and B are also now thought to be important indicators of heart risk. Apolipoprotein B may actually turn out to be a very accurate indicator of heart disease risk in women. 

High Blood Pressure

High blood pressure, or hypertension, has long been a proven cause of coronary artery disease. Blood pressure that measures above 140/90 in the doctor's office indicates hypertension, although experts now recommend that anyone with 135/99 should also monitor blood pressure at home.

Effects of Exercise and Sedentary Lifestyles

People who are sedentary are almost twice as likely to suffer heart attacks as are people who exercise regularly. Regular moderate aerobic exercise, such as brisk walking, lowers the heart rate and blood pressure, improves cholesterol, lowers blood sugar levels, fights blood clots, and reduces stress in both men and women. The brisker and longer the walks the more protection exercise offers for both men and women who are able to engage in more vigorous exercise. Healthy people can exercise without supervision. Even elderly people with unstable angina or who had a previous heart attack can benefit from a structured aerobics program. It should be noted, however, that sudden strenuous exercise (such as snow shoveling and mowing lawns) puts people with heart disease at risk for angina and heart attack. Activities that involve raising the arms above the head may also be risky. Patients with angina should never exercise shortly after eating. People with risk factors for heart disease should seek medical clearance and a detailed exercise prescription. And all people, including healthy individuals, should listen carefully to their bodies for signs of distress as they exercise. 

Diabetes and Insulin Resistance

Cardiovascular disease is two to four times more prevalent in people with diabetes. Common conditions occurring in diabetes, such as obesity and high blood pressure, partially account for this high risk. Insulin resistance, which occurs in people with diabetes and some nondiabetics, appears to be an independent risk factor for heart disease. According to a new study this risk is especially significant in elderly men. This condition occurs when insulin levels are normal to high but the body is unable to use the insulin to regulate metabolism of blood sugar and to store it for energy. In such cases, the body compensates by increasing insulin levels (hyperinsulinemia), which in turn increases triglyceride levels and reduces HDL cholesterol.

Obesity

Obesity is related to hypertension, diabetes, abnormal cholesterol levels, and lack of exercise, all conditions contributing to heart attack risk. Abdominal obesity (the "beer belly") poses a particular risk. Obesity in children is a greater risk for future heart trouble than a family history of heart disease. People who are overweight in middle age may still not completely reduce their risk for coronary artery disease later in life, even if they lose excess weight.

Homocysteine

Abnormally high blood levels of the amino acid homocysteine are strongly linked to an increased risk of coronary artery disease and stroke. Homocysteine may harm the lining of the arteries and contribute to blood clotting. Excessive levels occur with deficiencies of vitamins B6, B12, and folic acid. Some experts believe that high levels of homocysteine are only indicators, not causes, of heart disease, although some studies have suggested that taking daily supplements of vitamins B6 (3 mg) and folic acid (at least 400 micrograms) can reduce its risk. (Cold cereals are now fortified with folic acid.) 

Psychologic Factors

Stress. Mental stress is as important a trigger for angina as physical stress, and studies indicate that in people with heart disease it poses a higher risk for serious cardiac events, such as heart attacks, and even death from such events. In one study middle-aged women who were hostile, self conscious in public, and suppressed anger had an increased risk of developing atherosclerosis. And another recent one reported that angry young men were at higher risk for heart disease in later life.

Depression. In one 30-year study, men who were clinically depressed had a greater risk for heart disease and heart attack than men who were not depressed; this increased risk lasted for decades. Although some studies have failed to show an association between depression and heart disease in women, a 1998 study reported that depression is a significant risk factor for death in older women, particularly from heart disease, and the risk is equal to that from smoking or high blood pressure. Depression may even impair a patient's response to medication for heart disease. The more severe the depression, the more dangerous to the health, although some studies have indicated that even mild depression, including feelings of hopelessness, experienced over many years may harm the hearts in people with no early signs of heart disease. 

Genetic Factors

Research indicates that genetics are involved in the development of atherosclerosis. One important factor is apolipoprotein E (ApoE), which appears to affect cholesterol levels. One genetic variant called apoE4 is particularly associated with heart disease and a 1999 study suggests that it may be a significant risk factor for coronary artery disease in early middle age. (This variant also increases the risk for Alzheimer's disease.)